N-(mercaptoalkyl)omega-hydroxyalkylamides and their use as a reducing agent in a process for permanently deforming hair

ABSTRACT

An N-(mercaptoalkyl)ω-hydroxyalkylamide having the formula, ##STR1## wherein n is 2 or 3 and m is 2 to 5 inclusive is employed as a reducing agent in the first stage reducing operation of permanently deforming hair.

The present invention relates to newN-(mercaptoalkyl)ω-hydroxyalkylamides and their use, as reducing agents,in the permanent deformation of hair.

The technique of effecting a permanent deformation of hair comprises, ina first stage, the opening of the disulfide bonds of keratin (cystine)using a composition containing a reducing agent (reducing stage), thenpreferably after having rinsed the hair, reconstituting, in a secondstage, the said disulfide bonds by applying to the hair, under tension,an oxidizing composition (oxidation stage, also called a fixationstage), so as to give the desired form to the hair. This techniquepermits indifferently, to effect either waving the hair, or uncurling oruncrisping the hair.

Compositions to effect the first stage of a permanent waving operatingare generally provided in the form of lotions, creams, gels or powdersto be diluted in a liquid support and contain, preferably, a mercaptanas the reducing agent.

Among these latter, those currently employed are thioglycolic acid andthiolactic acid or a mixture of these acids, as well as their esters,for example, the monothioglycolate of glycerol or glycol.

These reducing agents which are particularly effective in reducing thedisulfide bonds of keratin include, principally, thioglycolic acid whichcan be considered as the product of choice in permanent wavingoperations. It provides a reduction in the amount of about 50%.

These reducing agents exhibit, however, a major disadvantage since theyemit bad odors, characteristic of sulfur compounds, which at timesrender the permanent waving operation distressing, not only for personswho undergo such an operation, but also for persons effecting such anoperation.

With a view to reducing this disadvantage, a perfume is generallyemployed to mask the odors.

Moreover, studies have been conducted with a view to perfecting newodorless reducing agents. Thus, in Japanese patent application (Kokai)No. 260.058/86, the use of N-mercaptoalkylgluconamides, which arewater-soluble compounds, having weak volatility and practically odorfree, have been proposed.

These N-mercaptoalkylgluconamides are obtained by reaction ofglucono-δ-lactone with an aminoalkanethiol.

These new reducing agents, if they provide a remedy for thedisadvantages of known reducing agents, they do not possess however theexcellent reducing properties enjoyed principally by thioglycolic acid.

It has now been noted, in a quite surprising fashion, that by employinga new class of mercaptoalkylamides, principallyN-(mercaptoalkyl)ω-hydroxyalkylamides, it is possible to remedy thedisadvantages of these various reducing agents.

The N-(mercaptoalkyl)ω-hydroxyalkylamides, according to the presentinvention, exhibit excellent reducing properties which are quitecomparable to those of thioglycolic acid but importantly they are odorfee.

The present invention relates to, as a new industrial product, watersoluble N-(mercaptoalkyl)ω-hydroxyalkylamides, having the formula##STR2## wherein

n is 2 or 3, and

m is 2 to 5 inclusive.

In accordance with a preferred embodiment of the present invention, n is2 and m is 3 or 4.

Representative N-(mercaptoalkyl)ω-hydroxyalkylamides of formula (I)above, include principally the following:

4-hydroxy N-(2-mercaptoalkyl) butyramide,

3-hydroxy N-(2-mercaptoethyl) propionamide,

5-hydroxy N-(2-mercaptoethyl) valeramide,

4-hydroxy N-(3-mercaptopropyl) butyramide,

6-hydroxy N-(2-mercaptoethyl) caproamide and

6-hydroxy N-(3-mercaptopropyl) caproamide.

Among these, 4-hydroxy N-(2-mercaptoethyl) butyramide is particularlypreferred.

The present invention also relates to a process for preparing themercaptoalkylamides in accordance with the invention, this processcomprising reacting a mercaptoalkylamine (1) with a lactone (2) inaccordance with the following reaction scheme: ##STR3##

The mercaptoalkylamines (1) employed are either 2-mercaptoethylamine orcysteamine (n=2) or 3-mercaptopropylamine (n=3).

The lactones (2) are β-propionolactone (m=2), γ-butyrolactone (m=3),valerolactone (m=4) or caprolactone (m=5).

The reaction of opening the lactone is generally carried out under aninert atmosphere in an alcohol such as methanol, ethanol, isopropanol orbutanol, and depending on the boiling point of the latter, at atemperature between 20° and 110° C.

The reaction time is generally long and can require several days so thatit can be advantageous not to employ a solvent and to mix themercaptoalkylamine and the lactone in stoichiometric proportions and tobring the mixture to a temperature between 20° and 80° C.

The evolution of the reaction is followed by dosage of thenon-transformed mercaptoalkylamine. When the reaction time is too long,an excess of mercaptoalkylamine can advantageously be employed and theexcess is removed at the end of the reaction by filtering the mixture ona sulfonic acid resin.

If, during the course of the reaction, a certain amount of thiol isoxidized to the corresponding disulfide, the reaction mixture is thendiluted by twice its volume with water and stirred in the presence of amixture of sulfonic resin and zinc powder for 3 to 10 hours.

The majority of the disulfide being reduced, the mixture is thenfiltered, thus resulting in a solution of the expected compound whichcan be used directly.

In accordance with a preferred embodiment of the process of the presentinvention, the mercaptoalkylamines can be employed in the hydrochlorideform considered as the primary material, the free amine being liberatedby the triethanolamine. In this case, after the end of the reaction theexpected compound is obtained with an equivalent of triethanolaminehydrochloride whose presence does not modify the properties of theN-(mercaptoalkyl)ω-hydroxyalkylamides of the present invention.

It can be advantageous to operate in an autoclave which eliminatessublimation problems of the cysteamine.

The present invention also relates to, as a new industrial product, thedisulfides of the compounds of formula (I) which can be represented bythe formula ##STR4## wherein

n and m have the same meanings as those given above for formula (I).

The disulfides are usefully employed in compositions called"self-neutralizers", i.e., they are combined with a thiol, such as forexample an N-(mercaptoalkyl)ω-hydroxyalkylamide of formula (I) above, inmolar amounts ranging from 0.5 to 2.5 and preferably from 1 to 2 (seeU.S. Pat. No. 3,768,490).

The disulfides of formula (II) in accordance with the present inventionare obtained by oxidizing the compounds of formula (I) either in air orby using, for example, H₂ O₂ in the optional presence of ferrous ions.

They can also be obtained by reacting a disulfide of formula (3) with alactone (2) in accordance with the following reaction scheme: ##STR5##

Representative disulfides of formula (II) above include, principally,the following:

bis (N-4-ethylhydroxy butyramide) disulfide,

bis (N-5-ethylhydroxy valeramide) disulfide,

bis (N-6-ethylhydroxy caproamide) disulfide,

bis (N-3-hydroxyethyl propionamide) disulfide,

bis (N-4-hydroxypropyl butyramide) disulfide and

bis (N-6-hydroxypropyl caproamide) disulfide.

The present invention also relates to a reducing composition, for thefirst stage of a permanent deformation operation of hair comprising, ina cosmetically acceptable vehicle, at least oneN-(mercaptoalkyl)ω-hydroxyalkylamide of formula (I) such as definedabove, as the reducing agent.

Preferably, the reducing agent is present in the composition accordingto the invention in an amount between 2 and 20 weight percent and,preferably, between 5 and 10 weight percent relative to the total weightof the reducing composition.

The pH of the composition is generally between 6.5 and 10 and isobtained using an alkaline agent such as, for example, ammonia,monoethanolamine, diethanolamine, triethanolamine, an alkaline orammonium carbonate or bicarbonate.

The reducing composition can also contain various ingredients such as,for example, cationic polymers such as those employed in thecompositions of French Pat. Nos. 79.32078 and 80.26421 or even cationicpolymers of the ionene type, such as those used in the compositions ofFrench Pat. No. 82.17364, softening agents and principally quaternaryammonium derivatives of lanolin, protein hydrolyzates, waxes, opacifyingagents, perfumes, dyes, non-ionic or cationic surface active agents,treating agents or even penetration agents such as urea, pyrrolidone orthiomorpholinone.

The reducing composition according to the invention can also be of theexothermic type, i.e., provoking a certain amount of heat duringapplication to the hair, which is agreeable to the person undergoing thefirst stage of the permanent or uncurling of the hair.

The vehicle of the compositions according to the invention is preferablywater or a hydroalcoholic solution of a lower alcohol such as ethanol,isopropanol or butanol.

When the compositions are intended for a hair uncurling or uncrispingoperation, the reducing composition is preferably in the form of a creamso as to maintain the hair as rigid or stiff as possible. These creamsare provided in the form of "heavy" emulsions, for example, those basedon glyceryl stearate, glycol stearate, self-emulsifying waxes, fattyalcohols, etc. Liquids or gels containing thickening agents, such ascarboxyvinyl polymers or copolymers which "glue" the hair can also beemployed so as to maintain the hair in a smooth position during thesetting period.

The present invention also relates to a hair waving process comprisingapplying a reducing composition, such as defined above, to wet hairpreviously rolled on rollers which have a diameter of 4 to 20 mm. Thecomposition can optionally be applied gradually on rolling the hair.

The reducing composition is then permitted to act on the hair for aperiod of time ranging from 5 to 60 minutes and preferably 5 to 30minutes. The hair is then thoroughly rinsed after which there is appliedto the rolled up hair, an oxidizing composition so as to reform thedisulfide bonds of the keratin during a setting period of 2 to 10minutes. After having removed the rollers the hair is thoroughly rinsed.

The oxidation composition, or oxidizing agent, is of the type currentlyemployed and contains as the oxidizing agent H₂ O₂, an alkaline bromate,a per salt or a mixture of an alkaline bromate and a per salt. Theconcentration of H₂ O₂ can vary from 3 to 10 volumes; the concentrationof alkaline bromate, from 2 to 12 weight percent and that of the persalt from 0.1 to 15 weight percent based on the total weight of theoxidation composition.

The present invention also relates to a process for uncurling oruncrisping the hair which comprises applying to the hair a reducingcomposition, according to the invention, submitting the hair to amechanical deformation so as to fix the hair in a new form, by smoothingthe hair with a comb having large teeth or with the back of the comb orwith the hand. After a setting period of 5 to 60 minutes, particularly 5to 30 minutes, the hair is again smoothed and then carefully rinsed. Theoxidation or fixing composition is then applied to the hair and left incontact therewith for about 2 to 10 minutes. The hair is then thoroughlyrinsed.

There are now given, as an illustration and without any limitingcharacter, several examples of preparing theN-(mercaptoalkyl)ω-hydroxyalkylamides and their disulfides, as well asseveral examples of compositions containing them.

EXAMPLE I Preparation of 4-hydroxy N-(2-mercaptoethyl)butyramide

(a) Reaction carried out at 80° C. starting with cysteamine

In a reactor, a mixture of 15.2 g of cysteamine and 15 cm³ ofγ-butyrolactone is stirred under an inert atmosphere for 5 hours at atemperature of about 80° C. The disappearance of the γ-butyrolactone isfollowed by vapor phase chromatography (VPC).

When the γ-butyrolactone is no longer detected in the reaction mixture,the latter is poured into 100 cm³ of water to which are added 10 g ofsulfonic resin, "Dowex 50" (partially hydrated at 45%) and 5 g of zincpowder so as to reduce the small amount of disulfide being formed duringthe course of the reaction. The whole is stirred for two hours atambient temperature and then filtered under an inert atmosphere. Aperfectly colorless aqueous solution is obtained. It is evaporated underreduced pressure and 25 g of 4-hydroxy N-(2-mercaptoethyl) butyramideare obtained.

It is a colorless liquid at ambient temperature.

The NMR¹ H 80 MHz conforms to the expected structure.

The thiol dosage in an acid medium is 95% and the elemental analysiscorresponds to a partially hydrated product: C₆ H₁₃ NO₂ S.1/2H₂ O

    ______________________________________                                                C       H      N        O    S                                        ______________________________________                                        Calculated                                                                              41.84     8.19   8.13   23.22                                                                              18.62                                  Found     41.59     7.83   8.56   22.84                                                                              18.85                                  ______________________________________                                    

(b) Reaction carried out at ambient temperature starting with cysteamine

In a round bottom flask, 7.72 g of cysteamine and 8.61 g ofγ-butyrolactone under an inert atmosphere are mixed. The mixture thusobtained is stirred for 10 days at ambient temperature. The initiallypasty medium progressively becomes homogeneous so as to give a clear andrelatively mobile liquid. The total transformation of theγ-butyrolactone is verified at this stage by VPC and that of thecysteamine by dosage with perchloric acid. The dosage of the thiol is100%.

15 g of 4-hydroxy N-(2-mercaptoethyl) butyramide are obtained.

(c) Reaction carried out starting with cysteamine hydrochloride

In a reactor there are introduced, at ambient temperature and under aninert atmosphere, 11.4 g of cysteamine hydrochloride and then slowly,with stirring, 13.5 cm³ of triethanolamine. To the resulting mixture,brought to a temperature of about 60° C., 7.7 cm³ of γ-butyrolactone areslowly added. At the end of the introduction the whole is brought to atemperature of 90° C. for three hours, at the end of which time all theγ-butyrolactone is transformed (VPC verification). 32 g of 4-hydroxyN-(2-mercaptoethyl) butyramide are obtained containing one equivalent oftriethanolamine hydrochloride in the form of a pasty white solid that isconditioned under an inert atmosphere.

The dosages correspond to the expected mixture.

(d) Reaction carried out starting with cysteamine hydrochloride withremoval of the triethanolamine hydrochloride formed

Into a reactor, fitted with a mechanical stirrer, 228 g of cysteaminehydrochloride are introduced and are placed under an argon atmosphere.270 cm³ of triethanolamine are slowly added, with stirring, over aperiod of about 1 hour 30 minutes. The pasty reaction mixture is thenbrought to 60° C. and, at this temperature, 155 cm³ of γ-butyrolactoneare slowly introduced. At the end of the addition, the whole is thenbrought for 8 hours at 80° C., at the end of which time all theγ-butyrolactone is transformed. 305 cm³ of absolute ethanol are thenintroduced and stirring is maintained at 60° C. for one-half hour.

The mixture is then cooled to about 15° C. and the triethanolaminehydrochloride is filtered. The filtrate is concentrated under reducedpressure to remove the ethanol.

250 g of 4-hydroxy N-(2-mercaptoethyl) butyramide are obtained.

EXAMPLE II Preparation of 5-hydroxy N-(2-mercaptoethyl) valeramide

A mixture, stirred under an inert atmosphere, of 5 g of cysteamine and6.05 cm³ of δ-valerolactone is brought to a temperature of about 60°-70°C. for 15 hours. The disappearance of the δ-valerolactone is followed byVPC. The reaction mixture is then poured into 100 cm³ of water and 10 gof acid resin, "Dowex 50" and 3 g of zinc powder are added. Theresulting mixture is stirred for 4 hours at ambient temperature and thenleft overnight. The next day the mixture is filtered and the water isevaporated under reduced pressure.

There are thus obtained 8 g of 5-hydroxy N-(2-mercaptoethyl) valeramidein the form of a colorless liquid whose NMR¹ H spectrum, as well as thethiol dosages and residual amine, conform to the expected structure.

EXAMPLE III Preparation of 6-hydroxy N-(2-mercaptoethyl) caproamide

A mixture, under an inert atmosphere, of 5 g of cysteamine and 7.2 cm³of ε-caprolactone is stirred for 6 hours at ambient temperature. It isthen left to stand overnight, after which the mixture is heated for 4hours at a temperature of about 60° C. At the end of this time all theε-caprolactone is transformed. The mixture is then poured into 100 cm³of water to which 10 g of acid resin, "Dowex 50" are added and then 3 gof powdered zinc. The whole is stirred for 4 hours at ambienttemperature. The water is then removed under reduced pressure and thereare obtained 10 g of 6-hydroxy N-(2-mercaptoethyl) caproamide in theform of a viscous liquid at ambient temperature whose NMR¹ H spectrumand thiol dosages and residual amine correspond to the expectedstructure.

EXAMPLE IV Preparation of bis (N-4-ethylhydroxy butyramide) disulfide

First Method

A solution of 20 g of 4-hydroxy N-(2-mercaptoethyl) butyramide in 300cm³ of anhydrous ethanol is stirred in air in the presence of 20 cm³ oftriethylamine for 48 hours at the end of which time the thiol istransformed into the corresponding disulfide. The solvent and thetriethylamine are removed by evaporation under a vacuum.

The resulting pasty product is finely divided by stirring in methylenechloride, filtered and then recrystallized in 200 cm³ of acetonitrile.

15 g of bis (N-4-ethylhydroxy butyramide) disulfide in the form of whitecrystals whose melting point is 102° C. are obtained.

    ______________________________________                                        Elemental analysis: C.sub.12 H.sub.24 N.sub.2 O.sub.4 S.sub.2                         C       H      N        O    S                                        ______________________________________                                        Calculated                                                                              44.42     7.47   8.64   19.72                                                                              19.76                                  Found     44.55     7.51   8.47   20.02                                                                              19.67                                  ______________________________________                                    

Second Method

Into a reactor there are introduced, successively and at ambienttemperature, 11.26 g (0.05 mole) of cysteamine hydrochloride, 14.92 g(0.1 mole) of triethanolamine, 8.61 g (0.1 mole) of γ-butyrolactone andfinally 20 cm³ of absolute ethanol. The resulting mixture is brought for4 hours to 80° C.

The reaction mixture is then filtered on fritted glass. The solid andthe filtrate are separately treated.

The solid is taken up in 75 cm³ of boiling acetonitrile. The insolublesare removed by filtration and the filtrate provides, on cooling, 8.3 gof a white solid.

The filtrate is evaporated to dryness and then taken up with 30 cm³ ofboiling acetonitrile. The insolubles are removed on fritted glass andthe filtrate gives, on cooling, 2.4 g of a white solid.

A total of 10.7 g of bis (N-4-ethylhydroxy butyramide) disulfide havinga melting point of 98°-100° C. are obtained.

The NMR¹ H 80 MHz spectrum conforms to the expected structure.

In accordance with the same operating procedures described above theother disulfides mentioned above have been obtained.

EXAMPLE V Preparation of bis (N-5-ethylhydroxy valeramide) disulfide

To a solution of 1.77 g (0.1 mole) of 5-hydroxy N-(2-mercaptoethyl)valeramide in 20 cm³ of absolute alcohol, cooled to +5° C., 4.6 cm³(0.045 mole) of 30% H₂ O₂ are slowly added.

Stirring is then maintained for 1 hour while letting the temperaturereturn to ambient temperature. The thiol dosage is negative. Thereaction medium is then evaporated to dryness under reduced pressure.After prolonged drying under a vacuum at ambient temperature, 1.5 g ofbis (N-5-ethylhydroxy valeramide) disulfide are obtained which slowlycrystallizes under the form of a white waxy solid.

The NMR¹ H 80 MHz spectrum conforms to the expected structure.

EXAMPLE VI Preparation of bis (N-6-ethylhydroxy caproamide) disulfide

To a solution of 1.92 g (0.1 mole) of 6-hydroxy N-(2-mercaptoethyl)caproamide in 20 cm³ of ethanol, cooled to +5° C., 5.0 cm³ (0.049 mole)of 30% H₂ O₂ are slowly added with stirring. After 2 hours of stirringat ambient temperature (thiol test negative) the solution is clarifiedby paper filtration and then evaporated to dryness under reducedpressure. After prolonged drying under a vacuum at ambient temperature1.7 g of bis (N-6-ethylhydroxy caproamide) disulfide in the form of athick pale yellow gel are obtained.

The NMR¹ 80 MHz spectrum conforms to the expected structure.

Composition Examples

I - In accordance with the invention, a permanent deformation reducingcomposition for hair is prepared by admixing the following ingredients:

    ______________________________________                                        4-hydroxy N-(2-mercaptoethyl butyramide                                                                 9      g                                            Ammonia, sufficient amount for pH = 9                                         Perfume                   0.1    g                                            Preservative              0.5    g                                            Demineralized water, sufficient amount for                                                              100    g                                            ______________________________________                                    

This composition is applied to moistened hair, previously rolled on hairsetting rollers. After permitting the composition to act for about 15minutes the hair is thoroughly rinsed with water. The followingoxidation composition is then applied to the hair:

    ______________________________________                                        H.sub.2 O.sub.2, sufficient amount for                                                               8       volumes                                        Stabilizer             0.3     g                                              Perfume                0.1     g                                              Lactic acid, sufficient amount for pH = 3                                     Demineralized water, sufficient amount for                                                           100     g                                              ______________________________________                                    

The oxidizing composition is permitted to act on the hair for about 10minutes. The rollers are removed and the hair is thoroughly rinsed withwater.

After drying under a hood the hair exhibits beautiful curls.

In this example the reducing composition can advantageously be replacedby one of the following reducing compositions:

    ______________________________________                                        (A)  4-hydroxy N-(2-mercaptoethyl butyramide)                                                                 12     g                                           Monoethanolamine, sufficient amount                                           for pH = 9                                                                    Perfume                    0.1    g                                           Preservative               0.5    g                                           Demineralized water, sufficient amount for                                                               100    g                                      (B)  5-hydroxy N-(2-mercaptoethyl) valeramide                                                                 10     g                                           Monoethanolamine, sufficient amount                                           for pH = 8.5                                                                  Perfume                    0.1    g                                           Preservative               0.5    g                                           Demineralized water, sufficient amount for                                                               100    g                                      (C)  6-hydroxy N-(2-mercaptoethyl) caproamide                                                                 7      g                                           Ammonia, sufficient amount for pH = 8.5                                       Perfume                    0.1    g                                           Preservative               0.5    g                                           Demineralized water, sufficient amount for                                                               100    g                                      ______________________________________                                    

II In accordance with the invention, a composition is prepared to effecta "self-neutralizing"permanent by admixing the following components:

    ______________________________________                                        4-hydroxy N-(2-mercaptoethyl) butyramide                                                                6.3    g                                            Bis (N-4-ethylhydroxy butyramide)                                                                       17.5   g                                            disulfide                                                                     Urea                      8      g                                            Perfume                   0.1    g                                            Preservative              0.5    g                                            Ammonia, sufficient amount for pH = 9.5                                       Water, sufficient amount for                                                                            100    g                                            ______________________________________                                    

This solution is applied to moistened hair, previously rolled up on hairsetting rollers and is permitted to remain in contact with the hair forabout 20 minutes. The rollers are removed and the hair is thoroughlyrinsed with water.

After drying under a hood the hair exhibits beautiful waves.

What is claimed is:
 1. N-(mercaptoalkyl)ω-hydroxyalkylamide having theformula ##STR6## wherein n is 2 or 3, andm is 2 to 5 inclusive.
 2. Thecompound of claim 1 wherein n is 2 and m is 3 or
 4. 3. The compound ofclaim 1 selected from4-hydroxy N-(2-mercaptoethyl) butyramide, 3-hydroxyN-(2-mercaptoethyl) propionamide, 5-hydroxy N-(2-mercaptoethyl)valeramide, 4-hydroxy N-(3-mercaptopropyl) butyramide, 6-hydroxyN-(2-mercaptoethyl) caproamide, and 6-hydroxy N-(3-mercaptopropyl)caproamide.
 4. A cosmetic reducing composition for the first stage of apermanent deformation operation for hair, comprising in a cosmeticallyacceptable vehicle, as a reducing agent, at least oneN-(mercaptoalkyl)ω-hydroxyalkylamide of claim
 1. 5. The cosmeticreducing composition of claim 4 wherein said reducing agent is presentin an amount ranging from 2 to 20 weight percent based on the totalweight of said composition.
 6. The cosmetic reducing composition ofclaim 4 wherein said reducing agent is present in an amount ranging from5 to 10 weight percent based on the total weight of said composition. 7.The cosmetic reducing composition of claim 4 having a pH between 6.5 and10.
 8. The cosmetic reducing composition of claim 4 which also includesat least one of a cationic polymer, a softening agent, a proteinhydrolyzate, a wax, an opacifying agent, a perfume, a dye, a non-ionicor cationic surface active agent, a treating agent or a penetrationagent.